Stabilized abietyl materials and process for making the same



iatented May 11, 1948 UNITED STATES P TENT OFFICE STABILIZED ABIETYL MATERIALS rnoouss FOR MAKING THE-SAME. V

. Seymour Yolles, Providenceflt; I assignor to t Ridbo Laboratories, Inc., Paterson; N. J a cor-' poration of New Jersey r No Drawing.

7 Claims.

. This invention relates to an improved COmDOSrite abietylor rosin material having increased resistance to oxidation. 4 V

I As is well known, vario us abietyl compounds, such as gum and wood rosins', rosin esters, rosin salts and other derivatives, are advantageous materials for many purposes but are subject to the serious 'drawbaclm of being unstable and readily oxidizabla' In addition liquid derivatives are also subject to rather rapid embrittlement.

To overcome the foregoing drawbacks, which are j highly disadvantageous for many purposes for which abietyl compounds are otherwise well suited, it has been proposed either to treat the material in a manner to' increase its stability, or to add to the material some anti-oxidant tending to' inhibit oxidation. Examples 'of the-first expedient are treatments for hydrogenating and treatments for disproportionating the rosin or other abietyl compound. As examples of the second expedient (anti-oxidants) it may be mentioned' that a number of different agents have been tried for'this purpose, including amines or. phenols of various types.

Various of the foregoing treatments and also variousofthe proposed anti-oxidants have'at least in part increased the stability of abietyl compounds, but both ,of these expedients are subject to disadvantages, some of whicharemem. tioned just below. i

. In the case of treatmentof the rosin or other abietyl compound to increase its stability, the.

treatment; process has frequently been relatively expensive-or complicated, frequently requiring theemployment of expensive agents and/or catalysts and/or equipment. On the other hand various; of the anti-oxidants which have been proposed have'been subject to the disadvantage that the anti-oxidant itself frequently yields dark colored reaction products upon agingor when exposed to oxidizing influences, thereby impairing the quality of the product. In addition, the anti-oxidants heretofore proposed-for use have customarily been of chemical compo:

sition'quite difierent from the abietyl compoun beingstabilized, as a result of which the antioxidant may, in a sense, he considered as an;

impurity.

J have discovgred that a composite abietyl ma-" pplication January 14, I944, Serial No. 518,254 I 1 j 2 terialwhich has enhanced resistance to oxidation may be prepared by mixing with a given abietyl compoundto be stabilized, a minor proportion of another abietyl compound, which latter is itself highly stable as against oxidation. In this way even very small percentages, such as 5%, ofa' stabilized rosin, when added to an unstable commercial rosin, will increase the stability of the rosin to a degree far in excess of that to be expected from the addition of such small quantities of the stabilized material.

Most advantageously, according to the invention, the stabilized abietyl compound to be added is of the same basic composition or structure as the material to which it is to be added. To 'illustrate, it is preferred in the case of rosins, to add a small percentage of a stabilized rosin; and in the case of a rosin ester to add a small percentage of a stabilizedrosin ester. In this way, in thecase'of anacidic rosin material, the .desired general physical properties of the material are not impaired as they would be in the event, forinstance, of adding asmall percentage of .a stabilized ester to an acidic rosin material. Correspondingly, where a rosin ester of increased stability is desired asthe final product, the desired ester'content is maintained when adding a small percentage of'a stabilized ester, whereas the ester content would be somewhat impaired if a stabilized acidic rosin material were to be added to an ester.

It is here pointed out that the characteristic instability'and ready 'oxidizability of most abietyl compounds isieoinmonly considered to result from the relatively high unsaturation which such compounds manifest. The abietyl molecule comprises a hydrophenanthrene nucleus usually incorporating two double bonds,'which is the source of the"high unsaturation. This characteristic unsaturation is present not only in rosin acids and commercial rosins, such as gum and wood rosins, but 'also inderivatives of various types, such as e'sters and salts made from the acidic rosinmaterial.

The invention is applicable to many different rosin or abietylcompounds, such, for instance, as gum or-woodrosins, rosin acids, such as abietic acidgrosinesters made with'various monohydric andfpolyhydricalcohols, rosin salts of inorganic 3 and organic monovalent and polyvalent cations, rosin alcohols, the esters of rosin alcohols, and in general, compounds containing the abietyl nucleus and sufiicient unsaturation to be easily oxidizable.

Although, as above indicated, the invention is adapted to abietyl compounds: in general, it is otespecial advantage in connection with abietyl compounds in which the molecule has an oxygencontaining substituent at the 1-position.

With respect to the stabilized material to be added, this addition'ingredient may be' prepared in any one'of a variety of ways,for instance, by disproportionation or by hydrogenation. The partially aromatized type of addition ingredient is particularly effective, especially'j li Jp'fepfared in the presence of a sulfurous treating a fo'r example, in accordance with copending applica;

filed July 3, 1943, now Patent 2,395,278, (disclosing S02 heat treatment of abietyl compounds to reduce the unsaturation thereof) I Illustrative examples of stabilized additiorringredients which may be employed are givenijust below.

A wood rosin may be treatedin accordance with the process of the said patent-byheating the same to a temperature of 225"v Ct for lhourswhile bubbling S02 through-the rosin; at arate of 2 by weight per hour. This: produces a rosin procluot having quite low unsaturation, -as evidenced. by a low iodine number, which, in a typical case, will be-about 60 (Hiibl),; whichcompares with a Hiibl iodine number of a typical untreated wood rosin at about 134. S02 stabilizatiommay be effected over a wide, range of'temperatures extending from about 180 C.,,t0, about-35o C.,,;-and the rate of passage of, S02 may. also be varied from about 1% upward, although 10% is usually even more thanrrequired. H V r,

In accordance with another J example, a gum rosin. is treated with about. 7%, of sulfur, the mixture. being heatedat a temperatureof from 200 C. to 215 C. ior 3 hours. This alsoiyieldsya highly stable producthaving low unsaturation, which is' eminently suited; to. begemployed as {an addition ingredient inv accordance with the; pros ent invention. Such a sulfur stabilized product in atypical case will havea Hiibl iodine number of about 40, as compared with an iodine-number of about 152 for the; untreated gum-rosin. Sulfur stabilization may be efiected over axwide range of temperatures. extending Zafrom about; 100... C, up-to about 350 C., andzthe amount of-suliur may also be varied, for-examplefifrom 0.5% up to or i,

I As another example a. acommercialrosinj product known as ,Staybelite" (madesby -Hercules Powder Company) may be -used, this material comprising in maior'part a hydrogenated. rosin acid. a r Still another example of a material whichmay be employed as an addition ingredient is fl-lyexf rosin (made by Hercules Powder Company) ,;this product being disproportionated by employment of a heat treatment in the presenceloi -acatalystbut: without any reactiveichemical.

. Stabilized esters may beused-,'suoh,as sulfur-or S02 treated methyl or glycerol esters o f aqidi c rosin materials, and also -Hercolyn,themethyl ester 'oi.Staybelite,? mentioned-instabove.

\ In addition to products of the-above inan tioned, more or less pure stabilized-abietylcompounds, such as dehydroabiet aac dnritgde ivai tives may also be utilized. Dehydroabieticacid poses;

4 is a partially aromatized rosin acid in which one of the three rings is aromatized.

From the foregoing it will be seen that stabilization ingredients of many difierent types may be utilized, a number of different examples of these being given hereinafter.

The characteristic product of the present invention is a composite material comprising two abietyl ingredients, one of which is relatively unstable or has relatively high unsaturation, and the other of whiohis relativelystable or has relati-vely low -uhsatu1ati0n, "the second ingredient constituting only a minor-"portion of the total composite material, for instance from about 1% to about 20% of the first ingredient.

when'employing upwards of about 2%, from 5% toaboutf15'% being quite efiective for most pur- Inpracticing theinvention, all that is needed byway of treatment is to bring about a thorough dispersion of the addition ingredient in the main mass of abietyl compound to be stabilized. This maybe done by powderizing the materials or melting them and mixing them. may also be efiect'ed in the presence of solvents Liquid tiorivative's mayb 'fiiixeddn the colii e., arisen temperature. Homogeneity the final product i the a only important factor i connection with preparingthecomposite'material. y I

In considering ineroregomg itshouldbfkeiit in'Jmind that'the'inventi'on'is of fiiijstlnctfadVah tagefor a number of reasonsjinoluding' thefact that only a very small proporti'or'roi thejmaterial need be'subjectedto' a special stabilization treatmer t; The cost of nand n'g and'oiniaieriaisnsjed isthereby greatly reduced as compared" withiap plication' of astabilizing 'treatment to'Ithe entire body of the material to bestab'ilizedr DIlfthef other hand by employing a stabilizedabietyl" comwe s ihe a on n iefas o a slant, the basic characteristics of the..-abietyl compound are not altered, which is in gl ist il iot contrast withvarious other types of anti oxidants e of n os d f i .u swim e "th stabilized additioningredients are not-of: a type yielding dark ireaotion products upon aging or exposure to oxidizing influences,-wh-ich is incontrast to manyt-prior-antioxidantswhich; in efie'ct, constitute impurities in thematerial ahd which are also subject to the further: disadvantage that. they themselves frequently produce oxidation raactioni products of dark color.

To test the oxidation resistanceof vafioiis of" grtly extended "as "compared with a pi-Hdiict I I I have found thatmostfadvantageous results are secured 5 not containing the addition ingredient of this invention."

M EXAMPLES ExAMPrEs 1-7" dicated in Table I just below.

I Table'I.-.WW wood rosin Supplemental Ingredient Induction F Period (hrs) .x. in Oxidation Type Per cent Test i Dehydroabietic acid 2 18.0 2 do 5 21. 5 3 WW Wood Rosin heat treated 5 17.0

with 0.5% sulfur. 4. WW Wood Rosin heat treated 5 20.7

with 10% sulfur. 5 Rosin crystals obtained from 5 48.0

liquid S01 extraction of WW Wood Rosin heat treated with 5% sulfur. Staybelite Rosin-a hydrogen- 16.0

ated rosin (Hercules Powder 0. 7 Hyex" Rosi.na disproportion- 5 20.0

etedS rosin (Hercules Powder o. WW Wood Rosin alone 2.0

EXAMPLE 8 In this example 10% of a stabilized WW gum rosin was added to commercial WW gum rosin. The supplemental ingredient was prepared by heating gum rosin for 3 hrs. at a temperature of 210-215 C. in the presence of l /2% of sulfur. Upon subjection to the oxidation test, the composite material was found to have an induction period of 23 hrs. This compares with an oxidation test of WW gum rosin alone which showed an induction period of only 2 hrs.

EXAMPLES 9-13 In this group of examples various stabilized esters were added as supplemental ingredients to the methyl ester of rosin. The nature of the supplemental ingredients used in the several examples and the results of the oxidation tests are indicated in Table 11 just below.

Table II .-Methyl ester In this example 5% of a stabilized ester gum C was added to a commercial ester gum C. The stabilized supplemental ingredient was prepared by heat treating ester gum in the presence of about 10% of sulfur. The composite material had an induction period of 29 hrs. in the oxidation test. This compared with a similar test of ester gum alone which showed an induction of only 1% hrs. I

Iclaimr 1 1. A methodior rendering a readily oxidiz'ableabietyl compound resistant to oxidation, which method comprises adding-to and dispersing in the said abietyl compound from 1% to 20% of an ingredient comprising at least a substantial proportion of a compound selected from the class consisting of disproportionated abietyl compounds and hydrogenated abietyl compounds.

2. A method in accordance with claim 1 in which the abietyl compound being treated and the compound contained in the ingredient difier' only in unsaturation.

3. A method for rendering resistant to oxidation an abietyl compound having an oxygen containing substituent at the 1-position, which method .comprises adding to and dispersing in the said compound from 1 to 20% of an ingredient comprising at least a substantial proportion of a second abietyl compound selected from the class consisting of disproportionated abietyl compounds and hydrogenated abietyl compounds.

4. A method in accordance with claim 3 in which the first compound and the second compound differ only in unsaturation.

5. A method for rendering readily oxidizable abietyl compounds resistant to oxidation, which method comprises adding thereto and dispersing therein a minor amount of an ingredient comprising'a compound selected from the class consisting of disproportionated abietyl compounds and hydrogenated abietyl compounds, the com pound in the said ingredient constituting 1% to 5% of the total weight of the abietyl compound being treated and the ingredient.

6. A method for rendering abietic acid resistant to oxidation which comprises adding to and dispersing in the abietic acid to be treated from 1 to 20% of an ingredient comprising at least a substantial proportion of a compound selected from the class consisting of disproportionated abietyl compounds and hydrogenated abietyl compounds.

7. A method in accordance with claim 3 in which the said compound is disproportionated abietic acid.

8. A method in accordance with claim 3 in which the said compound is hydrogenated abietic acid.

9. A method for rendering esters of abietic acid resistant to oxidation which comprises adding to and dispersing in the ester to be treated from 1 to 20% of an ingredient comprising at least a substantial proportion of a compound selected from the class consisting of disproportionated abietyl compounds and hydrogenated abietyl compounds.

10. A method in accordance with claim 9 in which the said compound is a disproportionated abietyl ester.

11. A method in accordance with claim 9 in which the said compound is a hydrogenated abietyl ester.

12. A method in accordance with claim 9 in which the said compound differs from the abietyl ester being treated only in unsaturation.

13. A method for rendering readily oxidizable rosin resistant to oxidation, which method comprises adding to and dispersing in the rosin from 1 to 20% of an ingredient comprising at least a substantial proportion of a substance selected from the class consisting of disproportionated 

